A poll of historical knowledge among Dutch by Volkskrant, Historisch Nieuwsblad and Andere Tijden, also asked questions about Islam and Dutch identity. A representative group of 1069 Dutch answered twenty multiple choice questions in the annual poll.
66% of the respondents did not agree with Princess Maxima that there's no such thing as Dutch identity. 56% said Islam was a threat to Dutch identity and 57% thought allowing large groups of immigrants was the biggest mistake in Dutch history. [ed. More than trading off New Amsterdam?]
In historical questions, the poll revealed a lack of knowledge. Many respondents overestimated Dutch involvement in the slave trade. Barely 21% answered correctly that the Netherlands made up 5% of the world slave trade.
Older people scored better than younger. The difference between ethnic Dutch and immigrants was small, 5.2 vs. 4.9.
Source: Volkskrant (Dutch)